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How are we connected to microbes?
Where do microbes live?
Microbes
Found all around us
In water
Ponds and stagnant water
Example:
Pond water
Stagnant water
In soil and air
Even in extreme places
Example:
Hot water springs
Snow cold zones
Inside living bodies
Even inside our gut
Example:
Bacteria in our intestine
- They are found almost everywhere.
- They live in water, soil, air, and food.
- Some even live inside our body, like in our gut.
Where can we find microorganisms?
| Where found | Example |
|---|---|
| In water | Pond and stagnant water |
| In soil | Garden soil |
| In air | Floating spores |
| In food | Bread, fruit |
| In our body | Bacteria in the gut |
What happens if we keep a food item outside for some time? Why?
Why does fruit rot or grow fuzzy when left out?
Food is left out in the open
A lemon, tomato or orange
↓
Microbes land on it
They are floating all around us
↓
They grow on the food
A powdery or cotton-like patch appears
↓
The food is spoiled — it has been infected by microbes
Fruit with Microoorganism growing on it
- Microbes float all around us.
- They land on food left out, grow, and spoil it.
How can we prevent food from being spoiled by microorganisms?
Salt
Sugar
Added in large amounts to pickles.
Added in large amounts to murabbas.
Acts as a preservative.
Acts as a preservative.
Microbes cannot grow in it.
Microbes cannot grow in it.
Pickles
Murabbas
- They contain a lot of salt or sugar.
- High salt or sugar stops microbes from growing.
- So these foods are preserved for a long time.
Example:
A salty pickle stays good for months without rotting.
Are all microorganisms the same size, or is there diversity?
- No — microorganisms show great diversity in shape and size.
| Shape | Seen in |
|---|---|
| Spherical | Some bacteria, some algae |
| Rod-shaped | Many bacteria |
| Comma-shaped | Some bacteria |
| Spiral | Some bacteria |
| Irregular | Amoeba |
📋 NCERT Question 6 — Design an experiment to test
Design an experiment to test that microorganisms need optimal temperature, air, and moisture for their growth.
View Answer →
📖 Important Definitions
- Microbe — Another name for a microorganism.
📝 Summary - What we have learnt
- Microbes are everywhere — water, soil, air, food and our gut.
- They spoil food, but salt and sugar preserve against them.
